Node-density aware interest packet forwarding in ad hoc network

ABSTRACT

Systems and techniques for node-density aware interest packet forwarding in a dynamic ad hoc information centric network (ICN) are described herein. For example, a next interest packet to forward may be obtained at a network node. A time period to hold the next interest packet before forwarding may be calculated based on node density in the network. The node may then broadcast the next interest packet upon expiration of a timer set to the time period and started when the next interest packet was obtained.

TECHNICAL HELD

Embodiments described herein generally relate to computer networking andmore specifically to node-density aware interest packet forwarding in adynamic ad hoc information centric network (ICN).

BACKGROUND

ICN is an umbrella term for a new networking paradigm in whichinformation itself is named and requested from the network instead ofhosts (e.g., machines that provide information). To get content, adevice requests named content from the network itself. The contentrequest may be called an interest and transmitted via an interestpacket. As the interest packet traverses network devices (e.g.,routers), a record of the interest is kept. When a device that hascontent matching the name in the interest is encountered, that devicemay send a data packet in response to the interest packet. Typically,the data packet is tracked back through the network to the source byfollowing the traces of the interest left in the network devices.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 illustrates an example of an ICN network stack, according to anembodiment.

FIG. 2 is an example of a traffic-density aware interest packetforwarding flow, according to an embodiment.

FIG. 3 is an example of a method for node-density aware interest packetforwarding in an ad hoc ICN, according to an embodiment.

FIG. 4 illustrates an example ICN, according to an embodiment.

FIG. 5 is a block diagram illustrating an example of a machine uponwhich one or more embodiments may be implemented.

DETAILED DESCRIPTION

Some operating scenarios generally use radio broadcasts as the physicallayer of an ICN, such as vehicular networks (e.g., ad hoc vehicle tovehicle (V2V), vehicle to roadside unit, etc.). As used herein, an adhoc network does not rely on a pre-existing infrastructure, but ratheris composed of various units that may change over time. Forwardinginterest packets via radio broadcast in a decentralized dynamic network,such as an ad hoc vehicle network, may incur significant overhead. Dueto the shared nature of the wireless medium, multiple nodes may receivethe interest packet and forward it by re-broadcasting it on the wirelessmedium. Thus, these forwarding nodes may start competing, causingbroadcast storm in the network.

A distributed timer-based forwarder select technique may be used toaddress broadcast. Here, each node calculates a timer value in adistributed fashion based on the node's geo-location and communicationcapability. A neighbor node (e.g., a node within broadcast range orwithin a defined spatial locality) with the smallest timer valuegenerally is elected as the next hop forwarder and re-broadcasts theinterest packet. Upon reception of the broadcast from the elected node,other neighboring nodes suppress their interest forwarding transmissionto avoid a broadcast storm. The timer calculation mechanism, however,does not take node density—or traffic density in vehicular network—intoconsideration.

For example, in a sparse network (e.g., few vehicles on a section ofroad), a timer for a node (e.g., vehicle) with weak a communication linkmay have a higher value, even though that node might he the only optionto propagate an interest packet because the other neighbors can't reacha portion of the nodes. Hence, here, end-to-end latency may be increasedif the timer is not adjusted according to node density. In a densenetwork, the timer may be coordinated with an application layer interestpacket generation rate. Without this coordination, a new interest packetmay collide with the ongoing propagation of the previous interest packetin the broadcast medium. Again, node density consideration may beimportant for faster and reliable interest packet forwarding. Theseissues may be exacerbated in time or safety critical applications.

To address some of the issues noted above, a unified interest packetforwarding timer to control the flow of interest packets from theapplication layer as well as interest packets forwarded from otherneighboring nodes is described below. A packet queue within the ICNlayer may be used to store interest packets if they are received whileanother interest packet is being served by the timer. Node density isconsidered when calculating tinier values. For example, weights may beassigned to the timer function based on node density. These techniquesmay decrease latency in networks with variable broadcast sparsity,benefiting many scenarios with time or safety critical communications.Additional details and examples are described below.

FIG. 1 illustrates an example of an ICN network stack, according to anembodiment. As illustrated, a packet queue and a node-density awaretimer calculator are integrated into the ICN layer 120 of the networkingprotocol stack. The packet queue is configured to store incominginterest packets from both the application layer 110 and neighboringnodes. In an example, the transfer of interest packet from the packetqueue to the ICN forwarding daemon is controlled by a single timer. Thistimer indirectly regulates the application layer interest packet rateand adjusts its timer value based on node density.

In an example, the forwarding timer calculates its value from the nodedensity based on the following:

${{timer}_{forwarding}(u)} = {{density}_{factor}\left( {{w_{1}{f\left( {{geoLoc}(u)} \right)}} + {w_{2}{\sum\limits_{v \in {{Neirhbors}{(u)}}}{{link}_{capacity}\left( {u,v} \right)}}}} \right)}$

where, u is the node, density_(factor) is a fraction between 0 and 1indicating the level of node density, W1 and W2 are two weight factorsrespectively applied to adjust the relative impacts of the location of uand the communication link capacity of u with neighboring nodes.

In an example, a node density estimator 105 that interacts with variouslayers of the stack is configured to collect node density information.As illustrated, the node density estimator 105 receives densityinformation from a vehicle to a vehicle-to-everything (V2X) protocolstack. For example, a V2X application 115 broadcasting a periodic beaconor basic safety message may contain the location or the speed of avehicle. The node density estimator 105 is configured to estimate nearreal-time node density with the availability of such information. Aneighbor discovery protocol of a V2X MAC layer 130, for example, mayprovide similar information. For example, node density may be estimatedbased on received signal strength information from the physical layer140.

The presence of additional information, such as that provided by the MAC130 or PRY 140 layers may provide more accurate results, however, notall components are needed in all implementations. Thus, for example afirst node may incorporate only that node density information receivedfrom the application layer 110 or 115, while another node mayincorporate only the PHY layer 140 information to calculate nodedensity. In an example, the forwarding timer calculator within the ICNlayer 120 interacts with the node density estimator 105 each time theforwarding timer re-calculates the timer value.

FIG. 2 is an example of a traffic-density aware interest packetforwarding flow, according to an embodiment.

Upon reception of an interest packet, such as from the application layer205 or another node 210, the node checks whether there is a timerrunning for an already scheduled interest packet (decision 225). Ifthere is no timer running, it will get real-time node-density estimationinformation from node density estimator circuitry and calculates a timervalue (operation 230). The node may then attach the received interestpacket to the timer (operation 235) before starting the timer (operation240). The attachment ensures that the proper interest packet isforwarded (operation 215) and dequeued (operation 220) upon expirationof the timer.

When there is an existing tinier running (decision 225), the node maycheck whether the name of the received interest packet matches the nameof the interest packet currently attached to running timer (decision245). If there is a match found (decision 245), the timer may be stopped(operation 250) and a new interest packet will be popped from the packetqueue (operation 220), the timer value will be calculated (operation230) for the newly popped interest (operation 235), and the timer isstarted (operation 240) as noted above. If there is no match found andthe node does not find similar interest packets in the packet queue(decision 255), the received interest packet will be pushed to packetqueue (operation 260).

However, if there are similar interest packet found in the queue(decision 255), the node removes that packet from the queue (operation265). The node may then take one or more of the following actionsdepending on the source of the interest packet. First, the node mayenqueue the new interest packet if it comes from the application layer(decision 270). This action may be made under the assumption that theapplication layer retransmitted the same interest packet. Second, thenode may discard the packet (operation 275) if it comes from aneighboring node (decision 270). Here, the node may assume that theinterest packet waiting in the queue has already been served by aneighboring node.

As noted above, if the timer fires (e.g., expires), the interest packetattached to the timer is sent to the ICN forwarding daemon—which managesthe PIT entry—that then forwards the interest packet via radio broadcast(operation 215). Then a new interest packet is popped from the packetqueue (operation 220) and the flow continues as noted above.

FIG. 3 is an example of a method 300 for node-density aware interestpacket forwarding in an ad hoc ICN, according to an embodiment. Theoperations of the method 300 are implemented in computing hardware, suchas that described in FIG. 4 or 5 (e.g., processing circuitry).

At operation 305, a next interest packet to forward is obtained. Here,obtaining the next interest packet may include receiving the interestpacket from an application on a node or from another node. In anexample, the interest packets that are created or arrive at the node arestored in a queue. In an example, to obtain the next interest packet,the next interest packet is at the top of the queue and it is dequeued.

in an example, the node ascertains whether an interest is unique in thequeue prior to enquiring the interest. In an example, uniqueness ismeasured by the interest packet's name. Thus, in an example, if thequeue already includes an interest with the same name as a newly createdor arrived interest, the node may either discard the queued interest infavor of the newer interest, or the node may discard the newer interestin favor of the queued interest.

At operation 310, the node calculates a time period to hold the nextinterest packet before forwarding. Thus, the interest will not betransmitted until the time period elapses. Here, the time period isbased on node density in the network. Thus, compared to traditionaltiming-based techniques, the denser the network, the longer the timeperiod, and the more sparse the network, the shorter the time period.This enables sparse networks to communicate more effectively by notimposing excessive timer periods for nodes based on poor network linkswhen there may not be better links among other nodes. Similarly, bylengthening the time period in dense networks, the chance that multiplenodes will attempt a simultaneous broadcast is reduced, which in turn,reduces the probability of collisions in wireless network.

In an example, the timer period is further based on link capacity of thenode to other nodes in the network. Here, link capacity may be measuredin several ways. For example, the node may count how many other nodes towhich it has a good link. The node may average available bandwidth to apopulation of other nodes. Other measurements that establish a basisindicating the node's position in the ad hoc network (e.g., in relationto other nodes) may also be used.

In an example, the time period combines the link capacity with the nodedensity. Here, as noted above, values derived from these elements may beadded together. In an example, a weight may be applied to each in orderto adjust the relative impact of each element on the timer period.

In an example, calculating the time period includes obtaining nodedensity information. Node density may come from several sources, such asMAC, PHY, or application layer processes. Thus, in an example, the nodedensity information is obtained from an application aware of othernodes. This may be prevalent in scenarios where the higher layerapplication is used to participate in the ad hoc network, such as in V2Vnetworks. In the scenarios, the V2V application may receive updatesindicating how many nodes are participating in the network, thegeographic spread of these nodes, etc.

In an example, the node density information is obtained from a mediaaccess (MAC) layer of the node. Some network discovery mechanisms thatoperate on the MAC layer may be used in this scenario. Here, as opposedto the possibly detailed information about the network, the MACdiscovery techniques are likely to illustrate how connected the node is.Thus, if the node discovers many other nodes, then the node may concludethat the network is locally dense, if it the entirety of the network issparse.

In an example, the node density information is obtained from a physicallayer (PHY) of the node. Like the MAC discovery, the PHY layer maydetermine connection characteristics to immediately (e.g., zero hops)reachable nodes. Not only may the node count how many other nodes arereachable, but the node may also evaluate the connection strength. Thesefactors establish density within the context of determining how to setthe time period to avoid undue delay (e.g., latency) in sparse networksand avoid flooding in dense networks.

in an example, the node density is a density factor based on thegeographic location of the node. Thus, the position of the node may beused to establish how dense the network is with respect to the node.Such information may be obtained, for example, from a higher-levelapplication that is more actively participating in the ad hoc processthat established the network. For example, a V2X application thatmaintains locations of network nodes. Here, the node's location mayestablish that the node is on the edge of the network, where nodedensity is lower. In an example, the density factor is between zero andone.

At operation 315, the next interest packet is broadcast upon expirationof a timer set to the time period. Generally, the timer is started whenthe time period is calculated, which is essentially when the nextinterest packet was obtained (e.g., dequeued). In an example, the noderefrains from broadcasting any interest packet while the timer isactive. In an example, a transceiver is used to broadcast the interestpacket via a wireless medium.

FIGS. 4 and 5 below provide additional details of the components inFIG. 1. For example, FIG. 4 illustrates several details and variationsin ICNs. FIG. 5 illustrates several examples of computer hardware thatcan be used to implement any of the components illustrated in FIG. 1.

FIG. 4 illustrates an example ICN, according to an embodiment ICNsoperate differently than traditional host-based (e.g., address-based)communication networks. ICN is an umbrella term for a networkingparadigm in which information itself is named and requested from thenetwork instead of hosts (e.g., machines that provide information). In ahost-based networking paradigm, such as used in the Internet protocol(IP), a device locates a host and requests content from the host. Thenetwork understands how to route (e.g., direct) packets based on theaddress specified in the packet. In contrast, ICN does not include arequest for a particular machine and does not use addresses. Instead, toget content, a device 405 (e.g., subscriber) requests named content fromthe network itself. The content request may be called an interest andtransmitted via an interest packet 430. As the interest packet traversesnetwork devices (e.g., network elements, routers, switches, hubs, etc.)such as network elements 410, 415, and 420 a record of the interest iskept, for example, in a pending interest table (PIT) at each networkelement. Thus, network element 410 maintains an entry in its PIT 435 forthe interest packet 430, network element 415 maintains the entry in itsPIT, and network element 420 maintains the entry in its PIT.

When a device, such as publisher 440, that has content matching the namein the interest packet 430 is encountered, that device 440 may send adata packet 445 in response to the interest packet 430. Typically, thedata packet 445 is tracked back through the network to the source (e.g.,device 405) by following the traces of the interest packet 430 left inthe network element PITs. Thus, the PIT 435 at each network elementestablishes a trail back to the subscriber 405 for the data packet 445to follow.

Matching the named data in an ICN may follow several strategies.Generally, the data is named hierarchically, such as with a universalresource identifier (URI). For example, a video may be namedwww.somedomain.com or videos or v8675309. Here, the hierarchy may beseen as the publisher, “www.somedomain.com,” a sub-category, “videos,”and the canonical identification “v8675309.” As an interest 430traverses the ICN, ICN network elements will generally attempt to matchthe name to a greatest degree. Thus, if an ICN element has a cached itemor route for both “www.somedomain.com or videos” and “www.somedomain.comor videos or v8675309,” the ICN element will match the later for aninterest packet 430 specifying “www.somedomain.com or videos orv8675309.” in an example, an expression may be used in matching by theICN device. For example, the interest packet may specify“www.somedomain.com or videos or v8675*” where ‘*’ is a wildcard. Thus,any cached item or route that includes the data other than the wildcardwill he matched.

Item matching involves matching the interest 430 to data cached in theICN element. Thus, for example, if the data 445 named in the interest430 is cached in network element 415, then the network element 415 willreturn the data 445 to the subscriber 405 via the network element 410.However, if the data 445 is not cached at network element 415, thenetwork element 415 routes the interest 430 on (e.g., to network element420). To facilitate routing, the network elements may use a forwardinginformation base 425 (FIB) to match named data to an interface (e.g.,physical port) for the route. Thus, the FIB 425 operates much like arouting table on a traditional network device.

In an example, additional meta-data may be attached to the interestpacket 430, the cached data, or the route (e.g., in the FIB 425), toprovide an additional level of matching. For example, the data name maybe specified as “www.somedomain.com or videos or v8675309,” but alsoinclude a version number—or timestamp, time range, endorsement, etc. inthis example, the interest packet 430 may specify the desired name, theversion number, or the version range. The matching may then locateroutes or cached data matching the name and perform the additionalcomparison of meta-data or the like to arrive at an ultimate decision asto whether data or a route matches the interest packet 430 forrespectively responding to the interest packet 430 with the data packet445 or forwarding the interest packet 430.

ICN has advantages over host-based networking because the data segmentsare individually named. This enables aggressive caching throughout thenetwork as a network element may provide a data packet 430 in responseto an interest 430 as easily as an original author 440. Accordingly, itis less likely that the same segment of the network will transmitduplicates of the same data requested by different devices.

Fine grained encryption is another feature of many ICN networks. Atypical data packet 445 includes a name for the data that matches thename in the interest packet 430. Further, the data packet 445 includesthe requested data and may include additional information to filtersimilarly named data (e.g., by creation time, expiration time, version,etc.). To address malicious entities providing false information underthe same name, the data packet 445 may also encrypt its contents with apublisher key or provide a cryptographic hash of the data and the name.Thus, knowing the key (e.g., from a certificate of an expected publisher440) enables the recipient to ascertain whether the data is from thatpublisher 440. This technique also facilitates the aggressive caching ofthe data packets 445 throughout the network because each data packet 445is self-contained and secure. In contrast, many host-based networks relyon encrypting a connection between two hosts to secure communications.This may increase latencies while connections are being established andprevents data caching by hiding the data from the network elements.

Example ICN networks include: content centric networking (CCN)—asspecified in the Internet Engineering Task Force (IETF) draftspecifications for CCNx 0.x and CCN 1.x; named data networking (NDN)—asspecified in the NDN technical report DND-0001; Data-Oriented NetworkArchitecture (DONA)—as presented at proceedings of the 2007 Associationfor Computing Machinery's (ACM) Special Interest Group on DataCommunications (SIGCOMM) conference on Applications, technologies,architectures, and protocols for computer communications; NamedFunctions Networking (NFN); 4WARD; Content Aware Searching, Retrievaland Streaming (COAST); Convergence of Fixed and Mobile BroadbandAccess/Aggregation Networks (COMBO); Content Mediator Architecture forContent-Aware Networks (COMET); CONVERGENCE; GreenICN; Network ofInformation NetInf); IP Over ICN (POINT); Publish-Subscribe InternetRouting Paradigm (PSIRP); Publish Subscribe Internet Technology(PURSUIT); Scalable and Adaptive Internet Solutions (SAIL); Universal,Mobile-Centric and Opportunistic Communications Architecture (UMOBILE);among others.

FIG. 5 illustrates a block diagram of an example machine 500 upon whichany one or more of the techniques (e.g., methodologies) discussed hereinmay perform. Examples, as described herein, may include, or may operateby, logic or a number of components, or mechanisms in the machine 500.Circuitry (e.g., processing circuitry) is a collection of circuitsimplemented in tangible entities of the machine 500 that includehardware (e.g., simple circuits, gates, logic, etc. Circuitry membershipmay be flexible over time. Circuitries include members that may, aloneor in combination, perform specified operations when operating. In anexample, hardware of the circuitry may be immutably designed to carryout a specific operation (e.g., hardwired). In an example, the hardwareof the circuitry may include variably connected physical components(e.g., execution units, transistors, simple circuits, etc.) including amachine readable medium physically modified (e.g., magnetically,electrically, moveable placement of invariant massed particles, etc.) toencode instructions of the specific operation. In connecting thephysical components, the underlying electrical properties of a hardwareconstituent are changed, for example, from an insulator to a conductoror vice versa. The instructions enable embedded hardware (e.g., theexecution units or a loading mechanism) to create members of thecircuitry in hardware via the variable connections to carry out portionsof the specific operation when in operation. Accordingly, in an example,the machine readable medium elements are part of the circuitry or arecommunicatively coupled to the other components of the circuitry whenthe device is operating. In an example, any of the physical componentsmay be used in more than one member of more than one circuitry. Forexample, under operation, execution units may be used in a first circuitof a first circuitry at one point in time and reused by a second circuitin the first circuitry, or by a third circuit in a second circuitry at adifferent time. Additional examples of these components with respect tothe machine 500 follow.

In alternative embodiments, the machine 500 may operate as a standalonedevice or may be connected (e.g., networked) to other machines. In anetworked deployment, the machine 500 may operate in the capacity of aserver machine, a client machine, or both in server-client networkenvironments. In an example, the machine 500 may act as a peer machinein peer-to-peer (P2P) (or other distributed) network environment. Themachine 500 may be a personal computer (PC), a tablet PC, a set-top box(SIB), a personal digital assistant (PDA), a mobile telephone, a webappliance, a network router, switch or bridge, or any machine capable ofexecuting instructions (sequential or otherwise) that specify actions tobe taken by that machine. Further, while only a single machine isillustrated, the term “machine” shall also be taken to include anycollection of machines that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein, such as cloud computing, software as aservice (SaaS), other computer cluster configurations,

The machine (e.g., computer system) 500 may include a hardware processor502 (e.g., a central processing unit (CPU), a graphics processing unit(GPU), a hardware processor core, or any combination thereof), a mainmemory 504, a static memory (e.g., memory or storage for firmware,microcode, a basic-input-output (BIOS), unified extensible firmwareinterface (UEFI), etc.) 506, and mass storage 508 (e.g., hard drive,tape drive, flash storage, or other block devices) some or all of whichmay communicate with each other via an interlink (e.g., bus) 530. Themachine 500 may further include a display unit 510, an alphanumericinput device 512 (e.g., a keyboard), and a user interface (UI)navigation device 514 (e.g., a mouse). In an example, the display unit510, input device 512 and UI navigation device 514 may be a touch screendisplay. The machine 500 may additionally include a storage device(e.g., drive unit) 508, a signal generation device 518 (e.g., aspeaker), a network interface device 520, and one or more sensors 516,such as a global positioning system (GPS) sensor, compass,accelerometer, or other sensor. The machine 500 may include an outputcontroller 528, such as a serial (e.g., universal serial bus (USB),parallel, or other wired or wireless infrared (IR), near fieldcommunication (NFC), etc. connection to communicate or control one ormore peripheral devices (e.g., a printer, card reader, etc.).

Registers of the processor 502, the main memory 504, the static memory506, or the mass storage 508 may be, or include, a machine readablemedium 522 on which is stored one or more sets of data structures orinstructions 524 (e.g., software) embodying or utilized by any one ormore of the techniques or functions described herein. The instructions524 may also reside, completely or at least partially, within any ofregisters of the processor 502, the main memory 504, the static memory506, or the mass storage 508 during execution thereof by the machine500. In an example, one or any combination of the hardware processor502, the main memory 504, the static memory 506, or the mass storage 508may constitute the machine readable media 522. While the machinereadable medium 522 is illustrated as a single medium, the term “machinereadable medium” may include a single medium or multiple media (e.g., acentralized or distributed database, and/or associated caches andservers) configured to store the one or more instructions 524.

The term “machine readable medium” may include any medium that iscapable of storing, encoding, or carrying instructions for execution bythe machine 500 and that cause the machine 500 to perform any one ormore of the techniques of the present disclosure, or that is capable ofstoring, encoding or carrying data structures used by or associated withsuch instructions. Non-limiting machine readable medium examples mayinclude solid-state memories, optical media, magnetic media, and signals(e.g., radio frequency signals, other photon based signals, soundsignals, etc.). In an example, a non-transitory machine readable mediumcomprises a machine readable medium with a plurality of particles havinginvariant (e.g., rest) mass, and thus are compositions of matter.Accordingly, non-transitory machine-readable media are machine readablemedia that do not include transitory propagating signals. Specificexamples of non-transitory machine readable media may include:non-volatile memory, such as semiconductor memory devices (e.g.,Electrically Programmable Read-Only Memory (EPROM), ElectricallyErasable Programmable Read-Only Memory (EEPROM)) and flash memorydevices; magnetic disks, such as internal hard disks and removabledisks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 524 may he further transmitted or received over acommunications network 526 using a transmission medium via the networkinterface device 520 utilizing any one of a number of transfer protocols(e.g., frame relay, internet protocol (IP), transmission controlprotocol (TCP), user datagram protocol (UDP), hypertext transferprotocol (HTTP), etc.). Example communication networks may include alocal area network (LAN), a wide area network (WAN), a packet datanetwork (e.g., the Internet), mobile telephone networks (e.g., cellularnetworks), Plain Old Telephone (POTS) networks, and wireless datanetworks (e.g., Institute of Electrical and Electronics Engineers (IEEE)802.11 family of standards known as Wi-Fi®, IEEE 802.16 family ofstandards known as WiMax®), IEEE 802.15.4 family of standards,peer-to-peer (P2P) networks, among others. In an example, the networkinterface device 520 may include one or more physical jacks (e.g.,Ethernet, coaxial, or phone jacks) or one or more antennas to connect tothe communications network 526. In an example, the network interfacedevice 520 may include a plurality of antennas to wirelessly communicateusing at least one of single-input multiple-output (SIMO),multiple-input multiple-output (MIMO), or multiple-input single-output(MISO) techniques. The term “transmission medium” shall be taken toinclude any intangible medium that is capable of storing, encoding orcarrying instructions for execution by the machine 500, and includesdigital or analog communications signals or other intangible medium tofacilitate communication of such software. A transmission medium is amachine readable medium.

Additional Notes & Examples

Example 1 is a device for node-density aware interest packet forwardingin a dynamic ad hoc information centric network (ICN), the deviceincluded in a node in a network and comprising: processing circuitry;and a memory including instructions that, when the device is inoperation, configure the processing circuitry to: obtain a next interestpacket to forward; calculate a time period to hold the next interestpacket before forwarding, the time period based on node density in thenetwork; and broadcast the next interest packet upon expiration of atimer set to the time period and started when the next interest packetwas obtained.

In Example 2, the subject matter of Example 1, wherein the node refrainsfrom broadcasting any interest packet while the timer is active.

In Example 3, the subject matter of any of Examples 1-2, wherein, tobroadcast the next interest packet, the processing circuitry uses atransceiver to broadcast the interest packet via a wireless medium.

In Example 4, the subject matter of any of Examples 1-3, wherein, tocalculate the time period, the processing circuitry obtains node densityinformation.

In Example 5, the subject matter of Example 4, wherein the node densityinformation is obtained from an application aware of other nodes.

In Example 6, the subject matter of any of Examples 4-5, wherein thenode density information is obtained from a media access (MAC) layer ofthe node.

In Example 7, the subject matter of any of Examples 4-6, wherein thenode density information is obtained from a physical layer (PHY) of thenode.

In Example 8, the subject matter of any of Examples 1-7, wherein thetime period is further based on link capacity of the node to other nodesin the network.

In Example 9, the subject matter of Example 8, wherein the time periodcombines the link capacity with the node density.

In Example 10, the subject matter of Example 9, wherein the node densityis a density factor based on the geographic location of the node.

In Example 11, the subject matter of Example 10, wherein the densityfactor is between zero and one.

In Example 12, the subject matter of any of Examples 1-11, wherein thatthe timer is used to coordinate forwarding interest packets from both alocal application layer and neighboring nodes.

Example 13 is a method for node-density aware interest packet forwardingin a dynamic ad hoc information centric network (ICN), the methodcomprising: obtaining a next interest packet to forward; calculating, bya node in a network, a time period to hold the next interest packetbefore forwarding, the time period based on node density in the network;and broadcasting the next interest packet upon expiration of a timer setto the time period and started when the next interest packet wasobtained.

In Example 14, the subject matter of Example 13, wherein the noderefrains from broadcasting any interest packet while the timer isactive.

In Example 15, the subject matter of any of Examples 13-14, whereinbroadcasting the next interest packet includes using a transceiver tobroadcast the interest packet via a wireless medium.

In Example 16, the subject matter of any of Examples 13-15, whereincalculating the time period includes obtaining node density information.

In Example 17, the subject matter of Example 16, wherein the nodedensity information is obtained from an application aware of othernodes.

In Example 18, the subject matter of any of Examples 16-17, wherein thenode density information is obtained from a media access (MAC) layer ofthe node.

In Example 19, the subject matter of any of Examples 16-18, wherein thenode density information is obtained from a physical layer (PHY) of thenode.

In Example 20, the subject matter of any of Examples 13-19, wherein thetime period is further based on link capacity of the node to other nodesin the network.

In Example 21, the subject matter of Example 20, wherein the time periodcombines the link capacity with the node density.

In Example 22, the subject matter of Example 21, wherein the nodedensity is a density factor based on the geographic location of thenode.

in Example 23, the subject matter of Example 22, wherein the densityfactor is between zero and one.

in Example 24, the subject matter of any of Examples 13-23, wherein thatthe timer is used to coordinate forwarding interest packets from both alocal application layer and neighboring nodes.

Example 25 is at least one machine-readable medium includinginstructions for node-density aware interest packet forwarding in adynamic ad hoc information centric network (ICN), the instructions, whenexecuted by processing circuitry, cause the processing circuitry toperform operations comprising: obtaining a next interest packet toforward; calculating, by a node in a network, a time period to hold thenext interest packet before forwarding, the time period based on nodedensity in the network; and broadcasting the next interest packet uponexpiration of a timer set to the time period and started when the nextinterest packet was obtained.

In Example 26, the subject matter of Example 25, wherein the noderefrains from broadcasting any interest packet while the timer isactive.

In Example 27, the subject matter of any of Examples 25-26, whereinbroadcasting the next interest packet includes using a transceiver tobroadcast the interest packet via a wireless medium.

In Example 28, the subject matter of any of Examples 25-27, whereincalculating the time period includes obtaining node density information.

In Example 29, the subject matter of Example 28, wherein the nodedensity information is obtained from an application aware of othernodes.

In Example 30, the subject matter of any of Examples 28-29, wherein thenode density information is obtained from a media access (MAC) layer ofthe node.

In Example 31, the subject matter of any of Examples 28-30, wherein thenode density information is obtained from a physical layer (PHY) of thenode.

In Example 32, the subject matter of any of Examples 25-31, wherein thetime period is further based on link capacity of the node to other nodesin the network.

in Example 33, the subject matter of Example 32, wherein the time periodcombines the link capacity with the node density.

In Example 34, the subject matter of Example 33, wherein the nodedensity is a density factor based on the geographic location of thenode.

In Example 35, the subject matter of Example 34, wherein the densityfactor is between zero and one.

In Example 36, the subject matter of any of Examples 25-35, wherein thatthe timer is used to coordinate forwarding interest packets from both alocal application layer and neighboring nodes.

Example 37 is a system for node-density aware interest packet forwardingin a dynamic ad hoc information centric network (ICN), the systemcomprising: means for obtaining a next interest packet to forward; meansfor calculating, by a node in a network, a time period to hold the nextinterest packet before forwarding, the time period based on node densityin the network; and means for broadcasting the next interest packet uponexpiration of a timer set to the time period and started when the nextinterest packet was obtained.

in Example 38, the subject matter of Example 37, wherein the noderefrains from broadcasting any interest packet while the timer isactive.

In Example 39, the subject matter of any of Examples 37-38, wherein themeans for broadcasting the next interest packet include means for usinga transceiver to broadcast the interest packet via a wireless medium.

In Example 40, the subject matter of any of Examples 37-39, wherein themeans for calculating the time period include means for obtaining nodedensity information.

In Example 41, the subject matter of Example 40, wherein the nodedensity information is obtained from an application aware of othernodes.

In Example 42, the subject matter of any of Examples 40-41, wherein thenode density information is obtained from a media access (MAC) layer ofthe node.

In Example 43, the subject matter of any of Examples 40-42, wherein thenode density information is obtained from a physical layer (PHY) of thenode.

In Example 44, the subject matter of any of Examples 37-43, wherein thetime period is further based on link capacity of the node to other nodesin the network.

in Example 45, the subject matter of Example 44, wherein the time periodcombines the link capacity with the node density.

in Example 46, the subject matter of Example 45, wherein the nodedensity is a density factor based on the geographic location of thenode.

In Example 47, the subject matter of Example 46, wherein the densityfactor is between zero and one.

In Example 48, the subject matter of any of Examples 37-47, wherein thatthe timer is used to coordinate forwarding interest packets from both alocal application layer and neighboring nodes.

Example 49 is at least one machine-readable medium includinginstructions that, when executed by processing circuitry, cause theprocessing circuitry to perform operations to implement of any ofExamples 1-48.

Example 50 is an apparatus comprising means to implement of any ofExamples 1-48.

Example 51 is a system to implement of any of Examples 1-48.

Example 52 is a method to implement of any of Examples 1-48.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments that may bepracticed. These embodiments are also referred to herein as “examples.”Such examples may include elements in addition to those shown ordescribed. However, the present inventors also contemplate examples inwhich only those elements shown or described are provided. Moreover, thepresent inventors also contemplate examples using any combination orpermutation of those elements shown or described (or one or more aspectsthereof), either with respect to a particular example (or one or moreaspects thereof), or with respect to other examples (or one or moreaspects thereof) shown or described herein.

All publications, patents, and patent documents referred to in thisdocument are incorporated by reference herein in their entirety, asthough individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended, that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments may be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is to allow thereader to quickly ascertain the nature of the technical disclosure andis submitted with the understanding that it will not be used tointerpret or limit the scope or meaning of the claims. Also, in theabove Detailed Description, various features may be grouped together tostreamline the disclosure. This should not be interpreted as intendingthat an unclaimed disclosed feature is essential to any claim. Rather,inventive subject matter may lie in less than all features of aparticular disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment. The scope of the embodiments should bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

What is claimed is:
 1. A device for node-density aware interest packetforwarding in a dynamic ad hoc information centric network (ICN), thedevice included in a node in a network and comprising: processingcircuitry; and a memory including instructions that, when the device isin operation, configure the processing circuitry to: obtain a nextinterest packet to forward; calculate a time period to hold the nextinterest packet before forwarding, the time period based on node densityin the network; and broadcast the next interest packet upon expirationof a timer set to the time period and started when the next interestpacket was obtained.
 2. The device of claim 1, wherein the node refrainsfrom broadcasting any interest packet while the timer is active.
 3. Thedevice of claim 1, wherein, to calculate the time period, the processingcircuitry obtains node density information.
 4. The device of claim 3,wherein the node density information is obtained from an applicationaware of other nodes.
 5. The device of claim 1, wherein the time periodis further based on link capacity of the node to other nodes in thenetwork.
 6. The device of claim 5, wherein the time period is calculatedfrom a combination of the link capacity with the node density.
 7. Thedevice of claim 6, wherein the node density is a density factor based onthe geographic location of the node.
 8. The device of claim 1, whereinthe timer is used to coordinate forwarding interest packets from both alocal application layer and neighboring nodes.
 9. A method fornode-density aware interest packet forwarding in a dynamic ad hocinformation centric network (ICN), the method comprising: obtaining anext interest packet to forward; calculating, by a node in a network, atime period to hold the next interest packet before forwarding, the timeperiod based on node density in the network; and broadcasting the nextinterest packet upon expiration of a timer set to the time period andstarted when the next interest packet was obtained.
 10. The method ofclaim 9, wherein the node refrains from broadcasting any interest packetwhile the timer is active.
 11. The method of claim 9, whereincalculating the time period includes obtaining node density information.12. The method of claim 11, wherein the node density information isobtained from an application aware of other nodes.
 13. The method ofclaim 9, wherein the time period is further based on link capacity ofthe node to other nodes in the network.
 14. The method of claim 13,wherein the time period is calculated from a combination of the linkcapacity with the node density.
 15. The method of claim 14, wherein thenode density is a density factor based on the geographic location of thenode.
 16. The method of claim 9, wherein the timer is used to coordinateforwarding interest packets from both a local application layer andneighboring nodes.
 17. At least one machine-readable medium includinginstructions for node-density aware interest packet forwarding in adynamic ad hoc information centric network (ICN), the instructions, whenexecuted by processing circuitry, cause the processing circuitry toperform operations comprising: obtaining a next interest packet toforward; calculating, by a node in a network, a time period to hold thenext interest packet before forwarding, the time period based on nodedensity in the network; and broadcasting the next interest packet uponexpiration of a timer set to the time period and started when the nextinterest packet was obtained.
 18. The at least one machine-readablemedium of claim 17, wherein the node refrains from broadcasting anyinterest packet while the timer is active.
 19. The at least onemachine-readable medium of claim 17, wherein calculating the time periodincludes obtaining node density information.
 20. The at least onemachine-readable medium of claim 19, wherein the node densityinformation is obtained from an application aware of other nodes. 21.The at least one machine-readable medium of claim 17, wherein the timeperiod is further based on link capacity of the node to other nodes inthe network.
 22. The at least one machine-readable medium of claim 21,wherein the time period is calculated from a combination of the linkcapacity with the node density.
 23. The at least one machine-readablemedium of claim 22, wherein the node density is a density factor basedon the geographic location of the node.
 24. The at least onemachine-readable medium of claim 17, wherein the timer is used tocoordinate forwarding interest packets from both a local applicationlayer and neighboring nodes.